The present invention relates in general to combination locks, and more particularly to combination locks of the gated tumbler wheel type operated by a dial with associated spindle and a driving cam, wherein the case and associated components facilitate installation in various positions, for example left or right hand positions, or vertical up or vertical down, without disassembling the lock.
Conventional locks of the class known as combination locks usually comprise three or four tumbler wheels which are loosely journaled in a coaxial, side-by-side spaced stack for rotation within a lock casing on a tubular arbor or tumbler post projecting inwardly from the front wall of the casing or from the rear cover plate. The lock dial, which usually has 100 peripheral calibration marks thereon, is affixed to a dial spindle which extends through the bore of the tumbler post and has keyed to the inner end thereof a disc-like drive cam which is likewise arranged coaxially with and spaced rearwardly from the stack of tumbler wheels. A drive pin projects forwardly from the drive cam and with a conventional fly rotatable through a limited arc and associated with the rearmost tumbler wheel, provides a lost motion coupling to drive the tumbler wheel in selected relation to the drive cam. A similar lost motion coupling is provided between each of the successive tumbler wheels so that each of the tumbler wheels may be driven upon predetermined rotation of the drive cam. A thin spacer washer is also customarily provided between each of the tumbler wheels. Each of the flies or fly members between the successive tumbler wheels and between the rearmost tumbler wheel and the drive cam typically comprise a ring portion journaled in concentric relation with the associated tumbler wheel and a radial projection which lies between a pair of stop shoulders disposed to abut portions of the radial projection and limit angular rotation of the fly to about 20.degree. or other desired limited angular range. A drive pin or lug projects from the adjacent tumbler wheel into position to abut the radial projection of the fly and transmit rotation to the adjacent tumbler wheel after the fly has moved through its predetermined lost motion angular range. Each of the tumbler wheels and the drive cam is provided with a peripheral notch or gate at a selected radial position on the drive cam and tumblers.
A fence lever, which is pivotally connected near one end on a reciprocative bolt member slidably supported in the lock casing, is provided with a depending nose near the opposite or free end of the fence lever which is designed to ride upon the drive cam periphery, in conventional combination locks, and has a bar or fence projecting laterally from the fence lever in overlying relation to the peripheries of the tumbler wheels. The position of the fence in relation to the length of the fence lever nose is usually such that the fence is spaced slightly outwardly from the peripheries of the tumbler wheels when the fence lever nose is riding on the drive cam periphery, in which position an abutment shoulder formation on the top wall of the lock case is adjacent and in the retraction path of the free end of the fence lever preventing movement of the bolt and the fence lever pivoted thereto toward retracted or unlocked position. When the tumbler wheel and drive cam gates are aligned to receive the fence and fence lever nose, the free end of the fence drops to a lower position sufficient to pass beneath the abutment shoulder formation and allow the fence lever and bolt to move to retracted or unlocked position.
The combination lock is opened, in the case of such conventional combination lock structures, by rotation of the dial in a predetermined sequence in clockwise and counterclockwise directions through predetermined numbers of revolutions to a series of numerical positions indicated by alignment of numbers or indicia on the lock dial with a fixed index adjacent the lock dial periphery, to dial a predetermined series of combination numbers and thereby effect angular rotation of the plurality of tumbler wheels to positions which result in alignment of the tumbler wheel peripheral gates with the fence, and the dial is then rotated to bring the drive cam gate to a position registered with the fence lever nose to cause the fence lever nose and fence to drop into the gates whereupon further rotation of the dial through a partial revolution in a predetermined direction achieves retraction of the bolt.
An object of the present invention, therefore, is the provision of a novel combination lock construction, wherein the mounting screws, the drive cam-to-spindle connection and combination alignment can be readily achieved from outside of or externally of the lock case, permitting significant reduction in installation time for safe manufacturers or others concerned with mounting such locks on safe doors or closures.
Another object of the present invention is the provision of a novel combination lock construction as described in the immediately preceding paragraph, wherein means such as a removable plastic insert is provided on the rear cover plate at a position allowing access to the drive cam while the cover plate is still assembled in and closes the case, for purposes of attaching the drive cam to the spindle in different desired angular positions for fixing the position of the drive cam on the spindle.
Yet another object of the present invention is the provision of a novel combination lock construction as described in the immediately preceding paragraph, wherein the access insert member is removable by a predetermined rotation thereof with a change key or similar tool to enable repositioning of the drive cam on the spindle.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.